The main objective of this research project is to look for evidence which links herpesvirus infections, especially herpes simplex virus type 2 (HSV-2), to human neurological disease, particularly multiple sclerosis. Thus far, these studies have included: 1) A comparison of the epidemiology of herpes simplex virus types 1 and 2 and that of multiple sclerosis, and 2) A search for CNS demyelination in experimental HSV-2 infections, and initial studies of the conditions which favor development of this pathology.